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                            <b>2.5.</b>
                        
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                            <b>2.6.</b>
                        
                        第6章：伪对象选择器
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                            <b>2.8.</b>
                        
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                            <b>5.</b>
                        
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                        第3章：Number
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                            <b>5.5.</b>
                        
                        第5章：运算符与字符串
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                        第7章：函数与作用域
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                            <b>5.8.</b>
                        
                        第8章：String方法
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                            <b>5.9.</b>
                        
                        第9章：数组方法
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                            <b>5.10.</b>
                        
                        第10章：定时器与排序
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                            <b>5.11.</b>
                        
                        第11章：Date与Math
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                            <b>5.12.</b>
                        
                        第12章：简单的DOM操作与垃圾回收
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                            <b>5.13.</b>
                        
                        第13章：DOM操作
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                            <b>5.14.</b>
                        
                        第14章：DOM修改样式
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                            <b>5.15.</b>
                        
                        第15章：DOM常用标签属性
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                            <b>5.16.</b>
                        
                        第16章：鼠标坐标与拖拽
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                            <b>5.17.</b>
                        
                        第17章：滚动条
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                            <b>5.18.</b>
                        
                        第18章：事件冒泡与事件代理
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                            <b>5.19.</b>
                        
                        第19章：原型对象
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                            <b>5.20.</b>
                        
                        第20章：this
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                            <b>5.21.</b>
                        
                        第21章：Ajax
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<h3 id="&#x8FD0;&#x7B97;&#x7B26;">&#x8FD0;&#x7B97;&#x7B26;</h3>
<pre><code>    // &#x7B97;&#x6570;&#x8FD0;&#x7B97;&#x7B26;
    // +&#x5177;&#x6709;&#x52A0;&#x6CD5;&#x548C;&#x62FC;&#x63A5;&#x7684;&#x4F5C;&#x7528;&#xFF0C;+&quot;1&quot;&#x4F1A;&#x8F6C;&#x5316;&#x4E3A;&#x6570;&#x503C;1
    console.log( + &quot;1&quot; + 1 )

    // -&#x53EA;&#x80FD;&#x662F;&#x51CF;&#x6CD5;&#x8FD0;&#x7B97;&#xFF0C;&#x5B57;&#x7B26;&#x4E32;&#x90FD;&#x4F1A;&#x8F6C;&#x5316;&#x4E3A;&#x6570;&#x503C;
    console.log( 1 - &quot;1&quot; )

    // &#x540C;&#x7406;&#xFF1A;&#x4E58;&#x9664;&#x4E5F;&#x662F;&#x5B57;&#x7B26;&#x4E32;&#x90FD;&#x4F1A;&#x8F6C;&#x5316;&#x4E3A;&#x6570;&#x503C;
    console.log( 1 * &quot;2&quot; )
    console.log( 1 / &quot;2&quot; )

    // &#x6C42;&#x4F59;
    console.log( 5 % &quot;2&quot; )

    var a = 0;
    a += 10;
    /* 
      &#x81EA;&#x589E; &#x5F53;&#x524D;&#x6570;&#x503C;&#x52A0;1
        a++&#x5373;&#x662F;&#x5B8C;&#x6210;&#x5F53;&#x524D;&#x4EE3;&#x7801;&#x7684;&#x6267;&#x884C;&#x540E;&#x518D;&#x81EA;&#x589E;
        ++a&#x5148;&#x81EA;&#x589E;&#xFF0C;&#x518D;&#x4F7F;&#x7528;

      &#x81EA;&#x51CF; &#x5F53;&#x524D;&#x6570;&#x503C;&#x51CF;1
          &#x548C;&#x81EA;&#x589E;&#x540C;&#x7406;
    */ 
    console.log( &quot;&#x81EA;&#x589E;&quot;, ++a )
    console.log( &quot;&#x81EA;&#x51CF;&quot;, --a )

    // &#x7B80;&#x4FBF;&#x5199;&#x6CD5;
    console.log( a -= 4 )        // 6
    console.log( a *= 4 )        // 24
    console.log( a /= 4 )        // 6
    console.log( a %= 4 )        // 2

    // &#x6BD4;&#x8F83;&#x8FD0;&#x7B97;&#x7B26;
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    // == &#x7B49;&#x4E8E; &#x4E0D;&#x5224;&#x65AD;&#x7C7B;&#x578B;&#xFF0C;&#x4F1A;&#x5E26;&#x6709;&#x9690;&#x5F62;&#x8F6C;&#x5316;
    console.log( &apos;5 == &quot;5&quot;&apos;, 5 == &quot;5&quot; )
    // === &#x5168;&#x7B49; &#x8FDE;&#x540C;&#x7C7B;&#x578B;&#x4E5F;&#x8FDB;&#x884C;&#x6BD4;&#x8F83;
    console.log( &apos;5 === &quot;5&quot;&apos;, 5 === &quot;5&quot; )
    // != &#x4E0D;&#x7B49;&#x4E8E; &#x4F1A;&#x5E26;&#x6709;&#x9690;&#x5F62;&#x8F6C;&#x5316;
    console.log( &apos;5 != &quot;5&quot;&apos;, 5 != &quot;5&quot; )
    // !== &#x4E0D;&#x5168;&#x7B49;&#x4E8E; &#x8FDE;&#x540C;&#x7C7B;&#x578B;&#x4E5F;&#x8FDB;&#x884C;&#x6BD4;&#x8F83;
    console.log( &apos;5 !== &quot;5&quot;&apos;, 5 !== &quot;5&quot; )



    // &#x903B;&#x8F91;&#x8FD0;&#x7B97;&#x7B26;
    // &amp;&amp; &#x4E0E;&#xFF08;&#x8C01;&#x548C;&#x8C01;&#xFF0C;&#x5E76;&#x5217;&#x7684;&#x5173;&#x7CFB;&#xFF09;&#x771F;&#x771F;&#x4E3A;&#x771F;&#xFF0C;&#x771F;&#x5047;&#x4E3A;&#x5047;&#xFF0C;
    console.log( false &amp;&amp; false )
    // || &#x6216;&#xFF08;&#x53D6;&#x4EFB;&#x610F;&#x4E00;&#x4E2A;&#x4E3A;&#x771F;&#x5373;&#x53EF;&#xFF09;
    console.log( true || false )
    // ! &#x975E; &#x53D6;&#x53CD;
    console.log( !true )

    // &#x5207;&#x6362;&#x65F6;
    var num2 = true;
    num2 = !num2;


    //            var num1 = prompt(&quot;&#x8F93;&#x5165;&#x4E00;&#x4E2A;&#x6570;&#x503C;&#xFF0C;&#x662F;&#x5426;&#x5728;0-10&#x4E4B;&#x95F4;&quot;);
    //             &#x5199;&#x6CD5;&#x4E0D;&#x89C4;&#x8303;&#xFF0C;&#x53EA;&#x80FD;&#x5224;&#x65AD;&#x5230;0&lt;num1
    //            console.log( 0 &lt; num1 &lt; 10 )
    //            console.log( 0 &lt; num1 &amp;&amp; num1 &lt; 10 )

    var num2 = 2 , num3 = 3;

    //&#x4F4D;&#x8FD0;&#x7B97;
    console.log( &quot;&#x4F4D;&#x8FD0;&#x7B97; &lt;&lt;&quot; , 4 &lt;&lt; 2 )        // a &lt;&lt; b &#x76F8;&#x5F53;&#x4E8E;  a * (2&#x7684;b&#x6B21;&#x65B9;)
    console.log( &quot;&#x4F4D;&#x8FD0;&#x7B97; &gt;&gt;&quot; , 32 &gt;&gt; 3 )        // a &gt;&gt; b &#x76F8;&#x5F53;&#x4E8E;  a / (2&#x7684;b&#x6B21;&#x65B9;)    &#x4E2A;&#x4EBA;&#x7406;&#x89E3;&#xFF1A;&#x503C;&#x9ED8;&#x8BA4;&#x53D6;&#x6574;&#xFF08;&#x5C0F;&#x6570;&#x70B9;&#x540E;&#x7684;&#x503C;&#x820D;&#x5F03;&#xFF09;
    // &#x65E0;&#x7B26;&#x53F7;&#x4F4D;&#x8FD0;&#x7B97; &#x8D1F;&#x6570;&#x5B58;&#x7684;&#x662F;&#x8865;&#x7801;&#xFF0C;&#x8FD0;&#x7B97;&#x65F6;&#x6C42;&#x56DE;&#x6B63;&#x503C;&#xFF0C;&#x518D;&#x6C42;&#x4F4D;&#x8FD0;&#x7B97;
    console.log( &quot;&#x4F4D;&#x8FD0;&#x7B97; &gt;&gt;&gt;&quot; , -9 &gt;&gt;&gt; 1 )
</code></pre><h3 id="&#x5B57;&#x7B26;&#x4E32;">&#x5B57;&#x7B26;&#x4E32;</h3>
<pre><code>    var str1 = &apos;&quot;UTF-8&quot;&apos;;

    // &#x62FC;&#x63A5;
    str1 = str1 + &quot;&#x62FC;&#x63A5;&quot;;
    str1 += &quot;&#x518D;&#x52A0;&quot;;
    console.log( str1 )

    // &#x957F;&#x5EA6;        &#x4ECE;1&#x5F00;&#x59CB;&#x6570;
    console.log( str1.length )

    // &#x4E0B;&#x6807;        &#x4ECE;0&#x5F00;&#x59CB;&#x6570;
    console.log( str1[0] )

    // unicode        &#x4E2D;&#x6587;&#x5B57;&#x7B26;&#x771F;&#x6B63;&#x7684;&#x6837;&#x5B50;&#xFF0C;&#x57FA;&#x672C;&#x6C49;&#x5B57;&#x8303;&#x56F4;4E00-9FA5
    var str2 = &quot;\u4E00\u9FA5&quot;;
    console.log(str2)

    // &#x6570;&#x5B57;
    console.log( Number(&quot;1234&quot;) )

    // &#x5E03;&#x5C14;&#x503C;    &#x7A7A;&#x5B57;&#x7B26;&#x4E32;&#x4E3A;false    &#x5176;&#x4F59;&#x90FD;&#x4E3A;true
    var str3 = &quot;123&quot;;
    console.log( str3.length,Boolean(str3.length) )

    /*
        Boolean
            &#x8F6C;&#x4E3A;false&#x7684;&#x6709;&quot;&quot;&#x7A7A;&#x5B57;&#x7B26;&#x4E32;&#x3001;0&#x3001;-0&#x3001;null&#x3001;undefined&#x3001;false

    */ 
    console.log( Boolean( true ) )

    // &#x62FC;&#x63A5;
    var str4 = &quot;-color&quot;;
    var str5 = &quot;background&quot;;
    console.log( str5 + str4 + &quot;:&quot;)

    // ES6&#x5B57;&#x7B26;&#x4E32;&#x62FC;&#x63A5;        ${&#x53D8;&#x91CF;}&#x8868;&#x793A;&#x5728;&#x8FD9;&#x4E2A;&#x4F4D;&#x7F6E;&#x63D2;&#x5165;
    console.log( `background${str4}:` )
</code></pre>
                    
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